The present invention relates to an active matrix display device and a method for producing a thin film transistor.
Hitherto, for example, according to the method disclosed in JP-A-9-96836, a plasma treatment is carried out using an inert element such as Ar to damage the interface of the back channel and allow the back channel area to contain 0.1–1.0 atom % of Ar, thereby increasing the surface state density and thus obtaining the effect to reduce the off-state current.
According to the scheme disclosed in JP-A-11-274514, the characteristics of thin film transistors are improved by subjecting amorphous silicon to dry etching, followed by carrying out a plasma treatment with helium.
Conventional liquid crystal display devices suffer from the problems that when coating type passivation films such as polyimide and polydisilazane or when wiring or picture element electrodes are provided on thin film transistors, the devices are affected by fixed charge in the passivation film or potential of the picture element electrode, resulting in an increase of off-state current to cause deterioration of display characteristics.